diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 03ec378..87855c1 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -10,10 +10,10 @@ jobs:
     with:
       coverage: codecov
       envs: |
-        - linux: py38-test-oldestdeps
-        - macos: py39-test
-        - windows: py310-test
-        - linux: py311-test
+        - linux: py39-test-oldestdeps
+        - macos: py310-test
+        - windows: py311-test
+        - linux: py312-test-devdeps
   publish:
     needs: tests
     uses: OpenAstronomy/github-actions-workflows/.github/workflows/publish_pure_python.yml@v1
diff --git a/.readthedocs.yml b/.readthedocs.yml
index 09d73e9..515fb63 100644
--- a/.readthedocs.yml
+++ b/.readthedocs.yml
@@ -1,10 +1,20 @@
+version: 2
+
 build:
-  image: latest
+  os: "ubuntu-22.04"
+  tools:
+    python: "3"
+
+sphinx:
+  builder: html
+  configuration: docs/conf.py
+  fail_on_warning: true
 
 python:
-  version: 3.8
-  pip_install: true
-  extra_requirements: ['docs']
+  install:
+    - method: pip
+      path: .
+      extra_requirements:
+        - docs
 
-# Don't build any extra formats
 formats: []
diff --git a/setup.cfg b/setup.cfg
index 34584b8..e67623d 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -14,12 +14,12 @@ github_project = astrofrog/sedfitter
 [options]
 zip_safe = False
 packages = find:
-python_requires = >=3.8
+python_requires = >=3.9
 setup_requires = setuptools_scm
 install_requires =
-    numpy>=1.18
-    scipy>=1.3
-    matplotlib>=3.1
+    numpy>=1.20
+    scipy>=1.8
+    matplotlib>=3.4
     astropy>=5.0
 
 
diff --git a/tox.ini b/tox.ini
index 4722aa6..aaeddca 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,16 +1,16 @@
 [tox]
 envlist =
-    py{37,38,39,310,311}-test{,-cov}
+    py{39,310,311,312}-test
     codestyle
 requires =
     setuptools >= 30.3.0
     pip >= 19.3.1
 isolated_build = true
-indexserver =
-    NIGHTLY = https://pypi.anaconda.org/scipy-wheels-nightly/simple
 
 [testenv]
-setenv = MPLBACKEND=agg
+setenv =
+    MPLBACKEND=agg
+    devdeps: PIP_EXTRA_INDEX_URL = https://pypi.anaconda.org/astropy/simple https://pypi.anaconda.org/liberfa/simple https://pypi.anaconda.org/scientific-python-nightly-wheels/simple
 changedir = .tmp/{envname}
 
 description =
@@ -19,21 +19,20 @@ description =
 
 deps =
     cov: coverage
-    oldestdeps: numpy==1.18.*
-    oldestdeps: scipy==1.3.*
-    oldestdeps: matplotlib==3.1.*
+    oldestdeps: numpy==1.20.*
+    oldestdeps: scipy==1.8.*
+    oldestdeps: matplotlib==3.4.*
     oldestdeps: astropy==5.0.*
-    devdeps: :NIGHTLY:numpy
-    devdeps: git+https://github.com/astropy/astropy.git#egg=astropy
+    devdeps: numpy>=0.0.dev0
+    devdeps: scipy>=0.0.dev0
+    devdeps: astropy>=0.0.dev0
 
 extras =
     test
 
 commands =
     pip freeze
-    !cov: pytest --pyargs sedfitter {toxinidir}/docs {posargs}
-    cov: pytest --pyargs sedfitter {toxinidir}/docs --cov sedfitter --cov-config={toxinidir}/setup.cfg {posargs}
-    cov: coverage xml -o {toxinidir}/coverage.xml
+    pytest --pyargs sedfitter {toxinidir}/docs --cov sedfitter --cov-config={toxinidir}/setup.cfg {posargs}
 
 [testenv:codestyle]
 skip_install = true